Crop performance and nitrogen use efficiency in maize under conservation agriculture coupled with sub-surface drip fertigation

Abstract

A field experiment was conducted in maize under medium-term conservation agriculture (CA) based maize- wheat system at B1SA-CIMMYT, Ladhowal, Punjab during £âar/2019 to assess the effect of CA* practices (CA with sub-surface drip irrigation) with variable N doses on maize. The CA* treatments were residue retained (WR) permanent bed (PB) with sub-surface drip fertigation (PB-SSD): without N (N0), 120 kg N/ha,150 kg N/ha applied in 4-equal (Eq) and differential splits ( Df); CA alone treatment includ PB furrow irrigation with 120 kg N/ha (PBWR- Furrow-N 120): conventional tillage (CT) invol ved furrow irrigation with 120 kg N/ha (CTWOR-Furrow-N120) and other treatments were residue removed (WOR) PB: PBWOR-without N (NO), with 120 kg N/ha, and 150 kg N/ha applied in four Eq-splits and Df-splits. The findings of the present experiment showed that the numerical value of yield attributing characters were highet under CA+ plots as compared to CA alone (PBWR-Furrow-N120) and CT (CTWOR-Furrow-N120). Biological yield of maize was significantly higher in all CA* plots as compared to CA alone and CT plots. Highest biological yield was recorded under PBWR-SSD-N 150 Df (23.45 t/ha). Highest no. of cobs (72800/ha), no. of grains/cob (605) and cob length (22.61 cm) along with dry matter resulted highest biological yield in PBWR-SSD-N 150 plots. The gfain N content remained statistically similar across all the N management plots, but in case of total N uptake, PBWR-SSD-N 150 Df (CA*) plots dominated due to higher biomass, Besides, CA+ based PBWR-SSD-N 120 (average of Df and Eq) registered 23-24% higher total N uptake than CA alone (PBWR- Furrow-N 120) and conventional (CTWOR-Furrow-N120) plots. Improved agronomic N use-efficiency was also recorded under CAT plots as compared to CA alone (36.4 kg/kg N) and CT (36.7 kg/kg N) plots.